Drill



Patented Mar. 17, .1942

DRHJL I Earl P. Welty, Center Valley, Pa., assignor to Bethlehem Pennsylvania Steel Company,

a corporation of Application May 29, 1940, Serial No. 337,755

(Cl. 77-67) I 5 Claims.

My invention relates to drills and particularly I drills for operating on metals.

tion of the body portion is out of contact with the work 20 during the boring operation and One of the objects of my invention is to provide a drill for boring accurate diameters of great depth.

Another object of my invention is to provide a drill which requires a much smaller amount of power for its operation in comparison with drills of the prior art.

Another object of my invention is to provide a dr ll which is constructed to obviate binding during the drilling operation thus eliminating breakage of the drill in the job.

A further object of my invention is to provide a drill having three boring portions, the first of which can be reground several times thus greatly prolonging the life of the drill.

A still further object of my invention is to provide a drill having a plurality of boring portions which successively increase in diameter from the initial cutting step so that the work may be easily drilled.

The novel features of my invention will be more fully understood from the following description and claims taken with the drawing in which Figure 1 is a plan view of .the drill shown in the material being drilled;

Figure 2 is an end view of the drill shown in Figure 1;

Figure 3 is a section taken of Figure 1; I

Figure 4 is a section taken along line 4-5 of Figure 1; and

Figure 5 is, a section taken along line 55 of Figure 1.

Referring to the drawing in detail, i designates a drill which is provided with a single flute H for removing chips, which are used by the boring operation. Drill I0 is further provided at along line 33 'its nose end with three boring portions l2, l3,'

and M. A duct I is provided to furnish oil for lubricating the drill and cleaning the chips from. the drill. Cross groove ll, hole l8, and hole l9 are provided to receive means for attaching the drill to a drill shank.

Referring to Figures 1 and 2. the nose or cutting end of drill ill is provided, as hereinbefore mentioned, with three boring portions I2, i3. and it which are substantially in the form of segments of a circle. The boring portion I2, is ground so as to form a heel 2| on a portion of the periphery of the body portion 22 approximately opposite the cutting edge 23, as is clearly shown in Figure 5. The heel 2! is so formed with relation to the cutting edge that the major portherefore binding of the drillin the work is prevented. The boring portion l3 has a. body portion- 24 of larger diameter than body portion 22 of. boring portion l2. The body portion 26 is provided on its periphery approximately opposite its cutting edge 25 with a heel portion 26 similar to heel 2|. The heels 2| and 26 also serve as bearing supports for the cutting edges 23 and 25, respectively. Boring portion 14 is provided with a cutting edge 21 which merges into the body portion 28. The body portion 28 is of larger diameter than the body portion 24 oi the boring por-- tion l3.

Upon reference to Figure 3 i will be observed I that the boring portion It is of circular formation and. has a cutting edge 21 which extends an appreciable distance outside the normal circumference of the boring portion M to contact with the work during the boring operation. The

body portion l4 does not have a-heel portion provided on the periphery of its body portion 28 opposite its cutting edge 2'! to contact with the work as do the boring portions l2 and I3. As a result the heels 2! and 26 of boring portions i2 and I3, respectively, will not only retain the cutting edges 23 and 25 of boring. portions l2 and I3, respectively, in contact with the work but will retain the cutting edge 21 ofboring portion it in contact with the work and, also retain the body portion 28 in spaced relation with the work.

During the boring operation the boring portion I 2 comes-in contact with the work 20 and bores a preliminary hole therein, the boring por tion l2 contacting the walls of the bore at its cutting edge 23 and at its heel 2|. The boring portion l3 which has a cutting action similar to that of boring portion l2 then comes into operation. This portion I3 is of greater diameter than the boring portion i2 and will also contact the walls of the bore only at its cutting edge 25 and its heel 26 of its body portion 24. The cutting edge 21 of the boring portion it then comes into operation. and contacts the work as shown in Figures 1 and 3, the body porti0n'28 being retained out oi contact with the workdue to' the heel portions 2! and 26 of the boring portions l2 and I3, respectively, contacting with the walls of the bore. As only the cutting edge 25 of the body portion 28 comes into contact with the work the binding and breakage of the body portion of the drill which invariably occur in other known drills, are eliminated, and also it will require considerably less power to operate the drill than boring portion or portions to engage the work are provided with a heel and the major portion of the main boring portion, such as indicated at I4, is in spaced relation with the work.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only suchlimitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A drill comprising a plurality of boring portions of difierent diameters, each of said boring portions having a body portion and a cutting edge, the boring portion of the smallest diameter having a heel formed on its body portion at a point remote from its cutting edge, adapted to contact the work and to retain the body portion of the boring portion of the largest diameter in spaced relation with the work.

2. A drill comprising an initial boring portion and a subsequent boring portion, said initial boring portion having a heel portion and a cutting edge to contact the work, said subsequent boring portion having acutting edge to contact the work and having a body portion adapted to be retained in spaced relation with the work. A

3. A drill comprising an initial boring portion, an intermediate boring portion, and a final boring portion,,said initial and intermediate boring portions each having a heel portion and a cutting edge to contact the work, said final boring portion having a cutting edge to contact the work and having a body portion adapted to be retained in spaced relation with the work.

4. A drill comprising a plurality of successively larger boring portions, each of said boring portions comprising a body portion, at least one of said boring portions having a cutting edge and a heel formed on the body portion adapted to contact the work and the largest of said boring portions having a cutting edge adapted to contact the work and a body portion to be retained in spaced relation with the work. a

5. A drill comprising a plurality of boring portions one of the boring portions being provided with a'heel and a cutting edge on the circumference thereof adapted to contact with the work and another of the boring portions having a cutting edge provided on the circumference thereof adapted to contact the work and the remainder of said boring portion adapted to be retained in spaced relation with the work.

EARL P. WELTY. 

